The present invention relates generally to the generation of electricity and more particularly to: (a) solar generation of electricity in combination with Rankine cycle generation of electricity; and (b) use of a Rankine cycle mechanism to generate electricity or do other work.
Solar energy is freely and daily available. It is a clean, non-polluting source of energy. Providing a reliable, long term, cost effective, efficient way of using sunlight to obtain electrical and thermal power has long been an unsolved problem, until the present invention.
It has been proposed that flat panel solar converters be used to convert direct sunlight into thermal or electrical energy.
Pedestal supported flat panels using direct sunlight to generate electricity were part of the Solar One project.
A circular, but concave reflector mounted on a single column or pedestal has been proposed. This approach was used on the Soleras water desalination project in Saudi Arabia and on the Solar Two project in Dagget, Calif.
Fixed position concave reflectors placed in an array and positioned in side by side rows on an incline have ben proposed. See U.S. Pat. No. 4,202,322. Such an installation was made at the Federal Correctional Institution at Phoenix, Ariz.
Tiltable elongated concave reflector assemblies have been utilized, such as the one at Barstow, Calif., owned by FPL Energy SEGS VIII and IX.
Solar Systems comprising bidirectionally controlled Fresnel lens and solar cell assemblies, utilizing direct sunlight, have been proposed. See, U.S. Pat. No. 4,649,899, for example. Also see, U.S. Pat. No. 4,245,153. Optical detectors for dual axis tracking of the sun are known.
The above-identified proposals and installations have failed to provide reliable, low cost, efficient, variable capacity systems by which solar energy is converted to electrical energy. A long felt need has existed for solar energy conversion plants which are reliable, efficient, cost effective and size variable to meet both low and high capacity demands for thermal and electrical energy.
Further, the prior art has failed to maximize production of electricity from a solar generator by not using effluent coolant (by which the temperature of the solar generator is controlled) as a secondary source for producing additional electricity. Also, the prior art fails to meaningfully identify a commercial way by which a heated coolant, having only a moderately elevated temperature, can be used to cost effectively produce electricity or do other work.
Heretofore, the Rankine cycle principle has been applied to convert thermal energy into mechanical energy into electricity only in very expensive complex plants comprising steam driven turbines typically operating within a temperature range of 850xc2x0 F. to 1100xc2x0 F., under high pressure. Fossil fuels are used to drive boilers which produce the high temperature, high pressure steam. Fossil fuel conversion efficiencies of these types of installations may be as high as approximately thirty seven percent (37%).
In brief summary, the present invention overcomes or substantially alleviates long term problems of the prior art by which solar energy is cost effectively converted to electrical energy and thermal energy and the thermal energy is thereafter converted to electrical energy as well. The present invention also provides for conversion of low temperature thermal energy, wherever obtained, to electrical energy using a novel Rankine cycle mechanism to drive an electrical generator in a cost effective way. The Rankine cycle mechanism can do other work as well. The present invention provides reliable, cost effective ways for conversion of solar energy and thermal energy to electricity, where the size of the system can be correlated to the desired capacity.
With the foregoing in mind, it is a primary object of the present invention to overcome or substantially alleviate long term problems of the prior art by which solar energy is converted to thermal energy and electrical energy and the thermal energy is thereafter converted to electrical energy.
Another paramount object of the present invention is to provide reliable, cost effective systems and methods for conversion of solar energy to electricity and thermal energy and to thereafter use the thermal energy to create additional electricity or do other work, where the size of any such system can be correlated to a desired capacity.
Still another important object is to provide systems and methods for the conversion of low temperature thermal energy, wherever obtained, to electrical energy or do other wok using a novel Rankine cycle mechanism by which a generator is driven or another work performing mechanism is driven, in a cost effective way.
It is a further valuable object to provide a novel energy transforming Rankine cycle mechanism and related methodology.
These and other objects and features of the present invention will be apparent from the detailed description taken with reference to accompanying drawings.